X87: Return different allocatable double register number for X87 turbofan / crankshaft seperately.

X87: Return different allocatable double register number for X87 turbofan / crankshaft seperately.

   Currently X87 turbofan backend use only one double register. But crankshaft needs to use more than 1
   double register. The reason is that the X87 register is stack-based and the register allocator use
   the same algorithm for all registers. So the backend of X87 needs to maintain the X87 stack status
   between basic blocks during code generation. But for Turbofan backend, it can only handle discrete
   platform-related LIRs. It's difficult to maintain the x87 stack status during different basic blocks.
   So we use the register configuration selection mechanism to return different register configuration
   for X87 turbofan and crankshaft seperately.

   This CL is a follow-up of https://codereview.chromium.org/1405673003/.

BUG=

Committed: https://crrev.com/4fe366f121103c36d85fe166b8e246ad56245d09
Cr-Commit-Position: refs/heads/master@{#31492}

[chunyang.dai, 2015-10-20 11:52:14]

chunyang.dai@intel.com changed reviewers:
+ danno@chromium.org, titzer@chromium.org, weiliang.lin@intel.com

[chunyang.dai, 2015-10-20 11:52:14]

Danno:

This CL is a follow-up of https://codereview.chromium.org/1405673003/. 

It will be landed after https://codereview.chromium.org/1405673003/.

PTAL.

thank.

[chunyang.dai, 2015-10-22 16:10:25]

Hello, Danno.
As https://codereview.chromium.org/1405673003/ is landed, Please
help to review this follow-up patch.

Thanks.

[danno, 2015-10-23 07:13:42]

The CQ bit was checked by danno@chromium.org

[danno, 2015-10-23 07:13:42]

lgtm

[commit-bot: I haz the power, 2015-10-23 07:31:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1413343002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1413343002/1

[commit-bot: I haz the power, 2015-10-23 07:34:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-23 07:34:17]

Patchset 1 (id:??) landed as
https://crrev.com/4fe366f121103c36d85fe166b8e246ad56245d09
Cr-Commit-Position: refs/heads/master@{#31492}